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This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/2.5/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Published by Oxford University Press on behalf of the International Epidemiological Association. International Journal of Epidemiology 2010;39:ii21–ii28 ß The Author 2010; all rights reserved. doi:10.1093/ije/dyq209

Estimating the number of people living with HIV/AIDS in China: 2003–09 Ning Wang,1y Lu Wang,1,y Zunyou Wu,1 Wei Guo,1 Xinhua Sun,2 Katharine Poundstone,1 Yu Wang3* and on behalf of the National Expert Group on HIV/AIDS Estimationz 1

National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China, Division of AIDS/STD, Bureau of Disease Control and Prevention, Ministry of Health, Beijing, China and 3Chinese Center for Disease Control and Prevention, Beijing, China

2

*Corresponding author. Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China. E-mail: [email protected] y These authors contributed equally to this work. z The membes of the The National Expert Group on HIV/AIDS Estimation are listed in the Acknowledgements.

Accepted

8 July 2010

Background Before 2003, little was known about the scale of China’s HIV/AIDS epidemic. In 2003, the Chinese government produced national estimates with support from the Joint United Nations Programme on HIV/AIDS, the World Health Organization and the United States Centers for Disease Control and Prevention. Subsequent national estimation exercises were carried out in 2005, 2007 and 2009. We describe these estimation processes and present the results of China’s HIV/AIDS estimation exercises from 2003 to 2009. Methods

The Workbook Method was used to generate national HIV/AIDS estimates. Data from the provincial level were used in 2003, data from the prefecture level were used in 2005 and data from the county level were used in 2007 and 2009. Data at the lowest level of aggregation were used to estimate risk group population size and HIV prevalence. Data from lower levels were combined into national estimates.

Results

At the end of 2003, 2005, 2007 and 2009, there were an estimated 0.84, 0.65, 0.70 and 0.74 million people living with HIV/AIDS in China, respectively, with an overall HIV prevalence of 0.05–0.06%. The number of new HIV infections decreased from 70 000 in 2005, to 50 000 in 2007, to 48 000 in 2009. Data quality improvements have increased the precision of China’s HIV estimates.

Conclusion Repeated estimates have improved understanding of the HIV/AIDS epidemic in China. HIV estimates are a valuable tool for guiding national AIDS policies evaluating HIV prevention and control programmes. Keywords

HIV/AIDS, estimation, Workbook, epidemiologic methods, China

Introduction How serious is China’s HIV epidemic? This question has generated significant speculation and debate over the past decade. In the 1990s, when HIV began to

spread quickly throughout China, little was known about the epidemic. The few data that were available suggested alarming increases in HIV prevalence among drug users (DUs)1,2 and plasma donors.3

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In 2002, the United Nations Theme Group on HIV/ AIDS in China issued a controversial report citing an estimated 1 million people living with HIV/AIDS (PLWHA) in China in 2001, with a projected 10 million infections by 2010 if countermeasures were not taken.4 Official sources at the time estimated that the number of HIV cases had risen from 300 000 in 1997 to 1 million in 2002.5 China’s HIV epidemic appeared to be escalating out of control, but without good data, it was hard to gauge the true scope of the epidemic. Beginning in 2003, the Chinese government began conducting systematic, biennial HIV/AIDS estimation exercises to assess the HIV epidemic at the national level. Working together with the Joint United Nations Programme on HIV/AIDS (UNAIDS), the World Health Organization (WHO) and the United States Centers for Disease Control and Prevention (US CDC), the Chinese government estimated that there were 840 000 PLWHA by the end of 2003, among whom 80 000 had developed AIDS.5 This estimation exercise revealed a number of data gaps: limited or absent data at the county level, a small number of epidemiological studies of HIV and sexually transmitted infections (STIs) and limited surveillance data from sites in high-prevalence areas.6 Because of the limited data available in 2003, estimates were prepared at the provincial level (the word ‘province’ in this article refers to all provinces, autonomous regions and municipalities including the Xingjiang Production and Construction Corps), making the precision. Since 2003, the Chinese government has taken measures to improve data availability and data quality. First, the government has expanded the HIV sentinel surveillance system from 148 sites in 2003 to 1029 sites in 2009.6,7 This has expanded geographic coverage and coverage of specific risk groups. For example, 25 surveillance sites assessed HIV trends among men who have sex with men (MSM) in 2009, compared with just 1 site in 2003 and 2005. Secondly, the government has established and expanded the HIV behavioural surveillance system, which provides essential data on risk behaviours in various subpopulations. Thirdly, the government has strengthened the HIV/AIDS case reporting system, including improving laboratory services to support HIV screening and confirmation testing. Finally, the government has conducted a number of special studies, including large-scale HIV screening among former plasma donors in central China.8 As more and more data have become available, China’s HIV/AIDS estimates have become increasingly reliable. In 2005, 2007 and 2009, China conducted three more rounds of HIV/AIDS estimation exercises using the Workbook Method recommended by the WHO and the UNAIDS.9–13 Here, we describe these estimation processes, review the results of these estimation exercises and outline the challenges ahead.

Methods The estimation process China’s national HIV estimates have been generated through consultative processes involving key stakeholders. In 2005, the National HIV Epidemic Estimation Working Group was formed to support national HIV/AIDS estimation processes.10 The working group includes domestic experts from the Ministry of Health (MOH) Expert Advisory Committee on HIV/ AIDS; the National Center of AIDS/STD Control and Prevention (NCAIDS) within the Chinese Center for Disease Control and Prevention (China CDC); Peking University; Tsinghua University; Fudan University; Peking Union Medical College; Renmin University; and other universities and organizations. The group also includes international experts from the WHO, the UNAIDS, the US CDC and other organizations. Over the course of the estimation processes in 2005, 2007 and 2009,9–11 the group met to review estimation guidelines, to train key provincial level staff, to provide technical support and to oversee estimation analyses. National guidelines have been established to guide the estimation process. In 2005, NCAIDS staff drafted guidelines to ensure comparability of data across geographical areas, along with an implementation manual.13 The guidelines and implementation manual were pilot tested in one province before being applied nationwide. In 2007, the guidelines and implementation manual were updated to reflect parameter adjustments, standardization of terms and definitions and rules for borrowing estimates across geographical areas in places where data were not available.14,15 Using national guidelines, provinces prepared draft HIV/AIDS estimates. In 2005, provincial estimates were based on prefecture-level Workbook spreadsheets. In 2007 and 2009, when more data were available, county-level Workbook spreadsheets were prepared. In 2005, 2007 and 2009, province-level Workbook spreadsheets were reviewed by regional working groups formed from the National HIV Epidemic Estimation Working Group. After these were reviewed, each provincial health bureau (or health department) and CDC jointly finalized the provincial estimates. NCAIDS staff then prepared national estimates with support from the National HIV Epidemic Estimation Working Group. The national estimates in 2005, 2007 and 2009 were reviewed by representatives from the UNAIDS and the WHO Geneva headquarters, and suggested adjustments were incorporated into the final national estimates. Prior to each estimation exercise, staff at each level were trained on how to produce HIV estimates using the Workbook Method. At the beginning of the process, senior technical staff from the national and provincial levels attended a training workshop organized by the UNAIDS and the WHO in Bangkok, Thailand. After senior technical staff received the

HIV/AIDS ESTIMATION IN CHINA

training, a national training workshop was organized with consultants hired by the UNAIDS, and provincial training workshops were organized in each province. By 2009, nearly 75% of the staff workers had already participated in at least one of the previous estimation exercises.

Data sources Demographic data Demographic data came primarily from publicly available census data in the previous 2 years, i.e. 2001, 2003, 2005 and 2007, from the National Bureau of Statistics of China, and adjusted by the number of annual reported births and deaths from national health statistics. HIV prevalence data HIV prevalence data came primarily from China’s HIV sentinel surveillance system. When possible, data from the previous 12 months were used. When recent data were not available, adjustments were made to previous data as considered necessary by local CDC officials. To generate HIV estimates for high-risk populations, sentinel surveillance data, behavioural surveillance survey (BSS) data, special epidemiological survey data, public security bureau (PSB) registration data and data from the published literature were used. Between 2003 and 2009, the number of HIV sentinel surveillance sites has grown (Table 1). Coverage of specific populations, such as MSM, has greatly improved (from 1 site in 2003 and 2005 to 25 sites in 2009). To generate HIV estimates for low-risk populations (e.g. the regular sex partners of high-risk individuals), different data sources were used depending on whether an area qualified as a low or high HIV prevalence area (